Process for applying anti-static finish to a textile material



United States Patent 3,379,565 PROCESS FOR APPLYING ANTI-STATIC FINISH TO A TEXTILE MATERIAL Chris A. Witcher, Jr., Pensacola, Fla., assignor to Monsanto Company, St. Louis, Mo., a corporation of Delaware No Drawing. Continuation-impart of application Ser. No. 247,301, Dec. 26, 1962. This application July 10, 1964, Ser. No. 381,921

6 Claims. (Cl. 117--139.5)

ABSTRACT OF THE DISCLOSURE In a process for applying an anti-static finish to a textile material by dispersing the finish in water, applying the resulting dispersion to the textile material and drying the applied dispersion on the material, bacterial degradation of the finish can be inhibited by carrying out the dispersion of the finish in water between 42 and 48 C. and maintaining the temperature of the resulting dispersion in that range until the drying of the dispersion on the textile material.

This application is a continuation-in-part of my copending application Ser. No. 247,301 which was filed on Dec. 26, 1962 and is now abandoned.

The term textile materials as employed in this specification includes natural and artificial textile fibers, yarns, and fabrics comprising cotton, linen, and other natural cellulose textile materials; viscose and cuprammonium and other regenerated cellulose textile material; wool, casein, alpaca, and other natural or synthetic protein textile materials; cellulose acetate and other cellulose derivative textile materials; and nylon, vinylchloride-vinylacetate copolymers, polyvinylidene polymers, acrylonitrile polymers, and other synthetic polymer or condensation product textile materials; all of which may be in the form of unspun fibers both natural and synthetic, staple fibers, yarns or continuous filaments, and woven and knitted fabrics.

In the manufacture and processing of textile materials, various finishes for the textile materials may be necessary for many purposes such as tinting to distinguish visually between two or more different types of textile yarns which would otherwise be identical in appearance and preventing the buildup of electrostatic charges. Electrostatic charges which may occur by the rubbing of the textile materials against each other or by their rubbing against other bodies give rise to various disadvantages which may show themselves in different ways dependent upon the nature of the fiber and the use thereof. Electrostatically charged textile materials may not only repel each other but may also attract and hold dirt, dust, etc.

Many compounds such as mono-, tri-, and polyethanolamine salts, starches, as well as a variety of adhesives and other materials such as fats, soaps, sulfonated oils and various solutions of colored pigments have been proposed as coatings to impart an antistatic or other effect to textile materials; however, none of these are entirely satisfactory. All are deficient in effectiveness either initially or sustained and are also deficient with respect to resistance to washing and dry cleaning. One of the major causes of these deficiencies may be due to bacterial action upon the coating.

Finishes or coatings used in the manufacture of textile materials from the synthetic, hydrophobic polymers such as polyamides, polyesters, and polyacrylonitrile derivatives comprise those listed above as well as many others varying widely in composition, but all such finishes are susceptible to bacterial degradation. Bacterial degradation of the finish may cause a myriad of problems both in the processing and the use of these textile materials.

3,379,565 Patented Apr. 23, 1968 ice Bacterial degradation of finishes is caused by bacterial growth in the finish, and this growth results in the formation of slimes which may deposit in finish preparation apparatus and finish application distribution systems, sometime to the extent that flow through the piping and other parts of the apparatus and distribution systems is severely restricted. This situation no only causes frequent shutdowns for cleaning and maintenance but also hinders or prevents the proper and uniform application of the desired finish to the textile material.

The presence of bacteria in prepared finish solutions also has an adverse effect upon the operability of textile materials in processing apparatus. Increased number of yarn breaks and flaring conditions of the yarn bundles may occur in handling the yarns at high linear speeds in processes as are well known in the textile industry. Bacterial growth in the antistatic finish also degrades the molecular structure of the finish, causing the formation of compounds therein which may have a deleterious effect on the strength of dyeing properties of the yarn as well as causing the formation of compounds which impart objectionable or rancid odors to textile materials made from the yarns.

Not only are these problems the result of bacterial growth, but the bacteria cells themselves contain inorganic materials such as iron, phosphorus, and silica which may deposit on yarn guides and other yarn direction controlling means such as guiding eyelets, bars, and pins which deposition may increase the friction of these devices, thereby causing increased yarn or thread breaks in processing as well as unnecessary looping and flaring of the yarn.

In general, finishes for textile materials are prepared and applied as aqueous dispersions of the finish component, and they may be applied by spraying, roll coating, or any other means which is convenient and suitable. It has been discovered that the organisms which attack the finishes causing the variation in the concentration of the finish on the textile material, the slime formation in apparatus, and the degree of effectiveness of the finish are of many types of air and water-borne organisms such as Pseudomonas aruginosa, Pseudomvnas pavonacea, one species of Actinomycetales and many others. These organisms reproduce prolifically in aqueous dispersions of the finishes when the finishes are being prepared and being applied to the textile materials.

Many bactericidal and bacteriostatic compounds are available to kill or inhibit the prolific growth of the water and air-borne organisms in aqueous dispersions of the finish during preparation and application; however, these compounds rapidly lose their effectiveness because of the drug-fast characteristics of the organisms involved or through chemical reactions within the finish dispersion itself. Heavy metals and heavy metal compounds such as silver, zinc, tributyl tin oxide, mercury, and others and volatile organic compounds such as alcohols, ketones, and ketone based materials, although known bactericides, are undesirable for use because of the known toxic properties of the vapors when inhaled by humans.

It is, therefore, an object of this invention to provide a process for reducing or eliminating bacterial growth in finishes for textile materials.

Another object is to provide a finish application process which will give textile materials a stable finish concentration.

A further object is to provide a process for the preparation and application of finishes to textile materials which will be free from slime formation.

A still further object of this invention is to provide a process for the application to textile materials of finishes which retain their desired properties for extended periods.

Other objects and advantages of this invention will be come apparent from the following description thereof.

In accordance with the present invention, it has been discovered that these and other objects are accomplished by mixing, preparing, storing and applying the desired finish at a temperature between 37 C. and 90 C. and preferably at a temperature of 42 C. to 48 C.

As an example, most, if not all, of the nylon filaments available today are manufactured by a melt spinning process. In such a process, the nylon polymer is heated to the molten or plastic state, but below the decomposition temperature thereof, and the molten or plastic mass is extruded at a constant rate and under pressure through small orifices in the face of a spinneret to form molten streams of polymer. The molten polymer streams are cooled and permitted to solidify into individual filaments which are then brought together and an aqueous dispersion of an antistatic finish is applied to the filaments.

The nylon filaments are impregnated with an aqueous dispersion or emulsion of the antistatic finish and the impregnated filaments are dried. For convenience, the antistatic finish is applied to the longitudinally traveling bundie of filaments by employment of a roller partly immersed in the composition or a wick material party immersed in the composition with the traveling filaments coming into contact with the wick. In place of this manner of application, the antistatic finish may be impregnated into the nylon filaments in any other suitable manner such as by the immersion of the filaments in a bath of an aqueous dispersion of the antistatic finish or by spraying or brushing the antistatic finish onto the filaments.

To orient the nylon filaments and thereby increase greatly their strength, they are stretched in one or more stages to a desired extent by attenuating them by means of thread advancing devices such as godets operated at a predetermined speed differential therebetween. It is quite advantageous to localize the point of drawing by the employment of a device such as snubbing pin located between the godets. The nylon filaments while traveling between the snubbing pin and the godets may be heated, and after being stretched, the filaments are collected, twisted, and a plurality of ends are plied into cord. The nylon cord may be wound onto bobbins or collected by any other means for further use.

In a process such as this, the deterioration of the antistatic finish is manifest by offensive smoking and fuming of the finish at points of heating, the breaking of the filaments during the stretching, and the flaring of the filaments during the collecting and twisting. Bacterial deterioration of the finish is also apparent at and in the apparatus used to apply the finish. Slimes form which coat the apparatus and plug distribution piping.

The aqueous dispersion of the antistatic finish may be prepared in the following manner. A desired antistatic finish and an emulsifying agent therefor are intimately agitated with a desired quantity of water at room temperature in a high-shear liquid blender for a sufiicient period of time to prepare emulsions exhibiting good stability.

The relative concentration of the antistatic finish in the aqueous dispersion thereof can be varied as necessary to obtain an impregnation of finish on the filaments is a desired amount. The concentration will depend, upon other things, on the kind of impregnation employed and on the form and kind of filaments treated. Emulsions ranging from 0.5 to about 25 percent or higher of the antistatic finish based on the weight of the aqueous dispersion are quite suitable for impregnating nylon filaments with antistatic finish in an amount from about 0.05 to percent based on the weight of the filaments.

By the process of this invention, aqueous dispersions of the antistatic finish are mixed or agitated at temperatures between 37 C. and 90 C. and preferably of 42 C. to 48 C.; the aqueous dispersion or emulsion of the antistatic finish and water thus prepared is maintained at temperatures between 37 C. and 90 C. and preferably of 42 C. to 48 C. until needed; and h pr pa d emulsion is applied to or impregnated into the textile material at a temperature between 37 C. and C. and preferably at a temperature of 42 C. to 48 C.

Any means for heating the aqueous dispersion of the finish during its preparation, storage and application to the textile material may be used, such as steam jacketed containers, heated water containers, or electrical immersion heaters. The source of energy selected and the means for applying this energy to the dispersion may be made on the basis of system economics and the availability of utilities.

The following examples are offered in order to illustrate further the present invention and the advantages thereof, it being understood that these are intended merely to be illustrative and not limiting.

Example I An aqueous emulsion of an antistatic finish comprising an acetylated monoglyceride, a methoxylated alcohol, and minor concentrations of a dye carrier and alcohol emulsifier were mixed with water in a Waring Blendor heated with a hot water bath to provide an aqueous emulsion temperature of 45 C. plus or minus 2 C. Sufficient antistatic finish was added to the heated water in the blender to prepare an approximately 15 percent oil and water emulsion. After mixing, the emulsion thus prepared was transferred to a hot water heated antistatic finish supply tank for roller coating addition to 8 nylon spinning positions. The finish supply tank for the roller coating of the nylon filaments was maintained at a tempera ture of 45 C. plus or minus 2 C. A similar sample of antistatic finish was mixed in an identical manner at room temperature and transferred to a finish supply tank maintained at room temperature for the roller coating addition to 8 nylon spinning positions adjacent thereto. Samples of antistatic finish were taken daily from both the unheated and heated supply tanks for a 3 Weeks period, and the nylon filaments thus treated were followed through the further stretching and texturing processes.

Results of the daily analysis of the finish showed that the bacterial population averaged 860,000 organisms per millimeter of aqueous dispersion in the unheated supply tank and 300 organisms per millimeter of aqueous dispersion in the heated supply tank, and that the number of filament yarn breaks in the hot stretching operation and the texturizing operation were decreased markedly for the yarn impregnated with the heated finish. Analysis of the finish concentration on the yarn showed the concentration of the antistatic finish was stable on yarn impregnated with hot finish having low bacterial population and very erratic for the yarn impregnated with finish from the unheated system.

No change was noted in the emulsion stability, the compOnent separation, or the chemical composition of the heated finish in the supply tank, and the percent water in the heated finish supply was reduced only 0.92 percent during the 3 weeks period.

Example II TABLE 1 Finish Unheated Heated organism/milliliter organism/milliliter TABLE 2 Process Heated finish Unheated finish Yarn beeaks in spinning Deceased Increased. Yarn breaks in texturizing o. 1" n 5 concentration on yarn Erratic.

Two samples of an aqueous emulsion of a lubricating and antistatic finish for textile materials comprising a mixture of mineral oil, sulfonated peanut oil, oleic acid and minor concentrations of diethylene glycol potassium hydroxide and triethanolamine were prepared by emulsifying the mixture with water in a Waring Blendor. Sufiicient of the finish mixture were added to the water in the blender to prepare an approximate 20% oil in water emulsion. Each of the two samples were stored for five hours at 47 C. 1- 2 C. and bacteria count was taken from each of the samples after mixing and then every two hours after the first hour. Table 3 below shows results of the sampling.

TABLE 3 Time, hrs. Sample 1 Sample 2 organism/milliliter organism/milliliter 2,400 000. No Growth. Do. Do.

As can be seen clearly from the results in the above Table 3, air and water borne bacteria which are present in the water and finish components at the start were unable to survive and did not multiply at the chosen temperature range. No apparent loss in sample volume was noted during the test period.

As can be seen clearly from the above examples, the novel process of providing heat to a finish for textile materials during the preparation, storage and application of that finish carries with it the definite advantages of reduced yarn breakage in the processing of the yarn and provides a means for maintaining a stable concentration of finish on the textile materials. These advantages, as

well as others obtained by reducing the amount or bacteria present on the textile materials, are obtained simply and at very low cost by the addition of simple heating systems to present processing equipment.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments thereof except as defined in the appended claims.

What is claimed is:

1. In a process for applying an anti-static finish to a textile material which comprises dispersing the anti-static finish in water, applying the resulting dispersion to the textile material and drying the applied dispersion on said material, the improvement of inhibiting bacterial degradation of the anti-static finish which comprises dispersing the finish, in water at a temperature in the range of 42 to 48 C. and maintaining the temperature of the resulting dispersion in said range until the drying of the applied dispersion on said material.

2. A process as defined in claim 1, in which the antistatic finish contains a mixture selected from the group consisting of sulfonated peanut oil and fatty acid esters, or sulfonated peanut oil and mineral oil.

3. A process as defined in claim 1, in which the resulting dispersion is an emulsion of the anti-static finish in water.

4. A process as defined in claim 1, in which the resulting dispersion contains from 0.5% to 25% by weight of the anti static finish.

5. A process as defined in claim 1, in which the applied dispersion on said material is dried until substantially all water is removed therefrom.

6. A process as defined in claim 1, in which the applied dispersion on the textile material contains between 0.05% and 5% of the anti-static finish by weight of said material.

References Cited UNITED STATES PATENTS 2,654,678 10/1953 Cresswell 117-139.5 2,709,665 5/1955 Campbell et a1. 117139.5 2,957,785 10/1960 Leatherland 117--138.8 3,033,704 5/1962 Sherrill et a1. 117139.5

WILLIAM D. MARTIN, Primary Examiner.

T. DAVIS, Assistant Examiner. 

